SSM框架-MyBatis篇

MyBatis总结

一、创建好工程文件,配置Pmop.xml文件

1.将mybatis库以及mysql-connector-java库加入到配置文件中;  2.将<resources>下的两个文件也加入到配置文件下,作用是让程序在预编译期可以使这两个文件夹下的文件也进行编译,代码如下:

  <build>    <finalName>MyBatis</finalName>    <resources>      <resource>        <directory>src/main/resources</directory>        <includes>          <include>**/*.properties</include>          <include>**/*.xml</include>          <include>**/*.tld</include>        </includes>        <filtering>false</filtering>      </resource>      <resource>        <directory>src/main/java</directory>        <includes>          <include>**/*.properties</include>          <include>**/*.xml</include>          <include>**/*.tld</include>        </includes>        <filtering>false</filtering>      </resource>    </resources>  </build></project>

二、将pom.xml文件配置完成后,创建对应的数据库以及表.

1.创建数据库表格时,方式多样,可以选择终端操作,也可以用Idea上的DataBase,还可以用DataGrip软件;
2.使用DataGrip软件,创建表格的代码如下:

CREATE DATABASE db0602;USE db0602;CREATE TABLE student (user_id INTEGER PRIMARY KEY AUTO_INCREMENT,user_name VARCHAR(200),user_des VARCHAR(200));INSERT  INTO student VALUES (NULL,'zhangsan');INSERT INTO student VALUES (NULL,'lisi');SELECT *FROM student ;

三、在resource文件夹下创建配置文件config.xml文件

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE configuration        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"        "http://mybatis.org/dtd/mybatis-3-config.dtd"><configuration>    <!--这个配置文件中,所有的标签都有严格的顺序-->    <environments default="deve">        <environment id="deve">            <transactionManager type="JDBC"/>            <dataSource type="POOLED">                <!--四个属性-->                <property name="driver" value="com.mysql.jdbc.Driver"/>                <property name="url" value="jdbc:mysql://localhost:3306/db0602"/>                <property name="username" value="root"/>                <property name="password" value="1qaz2wsx"/>            </dataSource>        </environment>    </environments>    <mappers>        <!--<mapper resource="com/lanou/mapper/StudentMapper.xml"></mapper>-->        <!--自动读取所有的mapper下的xml文件-->        <package name="com.lanou.mapper"/>    </mappers></configuration>

四、创建对应表格的实体类,在mapper文件夹下创建对应的接口文件和xml配置文件

1.根据上述的表格,需要创建的实体类student代码如下:

public class Student {    private Integer id;    private String name;}

2.创建接口文件StudentMapper,创建StudentMapper.xml文件

*在Mapper文件中写要执行的方法;
*在xml文件中写操作数据库的语句;
示例,将写一条查询表中所有数据的语句.

public interface StudentMapper {    //查询所有的学生    List<Student> allListStudent();}

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE mapper        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"        "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><!--namespace:一般写对应的接口路径--><mapper namespace="com.lanou.mapper.StudentMapper"><select id="allListStudent" resultMap="BaseMap">        SELECT * FROM student;    </select></mapper>

注意:需要在config.xml中将对应的mapper加入到标签<mapper>中

3.创建test类测试是否可以对数据库进行操作.

创建BatisTest类,具体代码如下:

public class BatisTest {    @Test    public void test1() throws IOException {        //1.加载config文件        String re = "config.xml";        InputStream stream = Resources.getResourceAsStream(re);        //2.创建SqlSessionFactory        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(stream);        //3.生成SqlSession        SqlSession session = factory.openSession();        //4.获取mapper对象        StudentMapper mapper                 = session.getMapper(StudentMapper.class);        //5.调用查询所有数据的方法获得结果        List<Student> students = mapper.allListStudent();        System.out.println(students);        //对数据库进行修改,需要使用session提交事务        session.commit();        session.close();    }}

结论:

运行结果没毛病,作为新手入坑篇很有用.